Hyaluronic acid (HA) is a high molecular weight glycosaminoglycan consisting of alternating D-glucuronic acid and N-acetylglueasamine and plays ex- tremely important roles in many biological processes. In this study...Hyaluronic acid (HA) is a high molecular weight glycosaminoglycan consisting of alternating D-glucuronic acid and N-acetylglueasamine and plays ex- tremely important roles in many biological processes. In this study, we optimized fermentation process for the production of HA by Streptococcus zooepidemicus ATCC35246, including fermentation broth composition and various fermentation parameters. The experimental results showed that the optimal fermentation broth composition was: glucose 45 g/L, yeast extract 10 g/L, tryptone 12 g/L, KH2PO4 2 g/L, K2HPO4 . 3H20 2 g/L, MgSO4 · 7H2O 2 g/L, and (NH4 )2SO4 0.4 g/L. The optimal parameters involved in fermentation was: liquid volume 20%, pH 6. 0, rotation speed 180 r/min, fermentation temperature 35 ℃, fermentation duration 18 h, CTAB concentration 25 mg/L. Under the optimized conditions, the yield of HA was 0. 305 g/L, which was dramatically improved by 43.87% compared to that of 0. 212 g/L before optimization.展开更多
The soft-sensor modeling for fermentation process based on standard support vector regression(SVR) needs to solve the quadratic programming problem(QPP) which will often lead to large computational burdens, slow conve...The soft-sensor modeling for fermentation process based on standard support vector regression(SVR) needs to solve the quadratic programming problem(QPP) which will often lead to large computational burdens, slow convergence rate, low solving efficiency, and etc. In order to overcome these problems, a method of soft-sensor modeling for fermentation process based on geometric SVR is presented. In the method, the problem of solving the SVR soft-sensor model is converted into the problem of finding the nearest points between two convex hulls (CHs) or reduced convex hulls (RCHs) in geometry. Then a geometric algorithm is adopted to generate soft-sensor models of fermentation process efficiently. Furthermore, a swarm energy conservation particle swarm optimization (SEC-PSO) algorithm is proposed to seek the optimal parameters of the augmented training sample sets, the RCH size, and the kernel function which are involved in geometric SVR modeling. The method is applied to the soft-sensor modeling for a penicillin fermentation process. The experimental results show that, compared with the method based on the standard SVR, the proposed method of soft-sensor modeling based on geometric SVR for fermentation process can generate accurate soft-sensor models and has much less amount of computation, faster convergence rate, and higher efficiency.展开更多
Biomass is a key parameter in fermentation process, directly influencing the performance of the fermentation system as well as the quality and yield of the targeted product. Hybrid soft-sensor modeling is a good metho...Biomass is a key parameter in fermentation process, directly influencing the performance of the fermentation system as well as the quality and yield of the targeted product. Hybrid soft-sensor modeling is a good method for on-line estimation of biomass. Structure of hybrid soft-sensor model is a key to improve the estimating accuracy. In this paper, a forward heuristic breadth-first reasoning approach based on rule match is proposed for constructing structure of hybrid model. First, strategy of forward heuristic reasoning about facts is introduced, which can reason complex hybrid model structure in the event of few known facts. Second, rule match degree is defined to obtain higher esti- mating accuracy. The experiment results of Nosiheptide fermentation process show that the hybrid modeling process can estimate biomass with higher accuracy by adding transcendental knowledge and partial mechanism to the process.展开更多
Due to its nutritional values, cassava has become an unavailable food and is one of the essential foods in the Republic of Congo. Fermentation of tubers is still traditional. Fiftyrod-shaped spore-forming bacteria wer...Due to its nutritional values, cassava has become an unavailable food and is one of the essential foods in the Republic of Congo. Fermentation of tubers is still traditional. Fiftyrod-shaped spore-forming bacteria were screened and carried out in batch mode for the fermentation abilities of cassava tubers in order to develop biotechnological starter. The Penetrometry Index (PI) has been used to screen bacteria and 16SrRNA as well as <i>fibE</i>one step multiplex PCR which were used to molecularly identify isolates. Emulsification Index, Proteolytic as well as amylolytic, and cellulolytic activities of some strains were quantitatively evaluated for prooving orgaleptic characterics. As results <i>Bacillus subtilis</i> (MT994787), <i>Bacillus subtillis</i> (MT994789), <i>Bacillus tequilensis</i> (MT994788), <i>Bacillus safensis</i>, and <i>Bacillus subtilis</i> have been identified. Single isolates were able to ferment tubers in 48 h and 72 hours meanwhile <i>Bacillus</i> consortia were able to shift fermentation of tubers from 48 hours to 24 hours. The consortium could be used as the major bacterial starters. Strains were associated with the ability to secrete biomolecules including biosurfactants, protease, amylase and cellulase.展开更多
Biosensors, which are the products of the biotechnology industry, are among the key projects of the 7th, 8th, and 9th Fiveyear Plans of China Science & Technology Developing Programs, respectively, and they play an i...Biosensors, which are the products of the biotechnology industry, are among the key projects of the 7th, 8th, and 9th Fiveyear Plans of China Science & Technology Developing Programs, respectively, and they play an important role in developing and reforming traditional biotechnology. SBA series biosensor analyzer, as the only one commercial biosensor in China, has attracted lots of attention in the process of information gathering and measurement for biological industry with the development of technology and society. In this paper, we presented an overview of the most important contributions dealing with the monitoring of the biochemical analytes in fermentation processes using SBA series biosensor analyzers in China. Future trends of the biosensor analyzer in China were also mentioned in the last section.展开更多
Papaya,a tropical fruit was used as the raw material to produce sauerkraut in the study.Three lactic acid bacteria strains isolated from papaya were added to the sauerkraut to facilitate the fermentation of papaya sau...Papaya,a tropical fruit was used as the raw material to produce sauerkraut in the study.Three lactic acid bacteria strains isolated from papaya were added to the sauerkraut to facilitate the fermentation of papaya sauerkraut.In the fermentation process,the dynamic changes of total acid in sauerkrauts at different levels of sugar concentration,salt concentration,inoculation and temperature were studied.The response surface method was used to study the effects of changes in multiple factors at the same time.On the basis of“one-variable-at-a-time”approach,the response surface method optimized papaya sauerkraut fermentation process.According to the change of total acid in single factor,29 experiments were designed by 4×3 factorial central composite design.The optimum fermentation conditions were obtained as follows:sugar at 3.8%,salt at 2.8%,inoculation at 5%,and temperature at 31℃.展开更多
A cellular automata model to simulate penicillin fed-batch fermentation process(CAPFM)was established in this study,based on a morphologically structured dynamic penicillin production model,that is in turn based on th...A cellular automata model to simulate penicillin fed-batch fermentation process(CAPFM)was established in this study,based on a morphologically structured dynamic penicillin production model,that is in turn based on the growth mechanism of penicillin producing microorganisms and the characteristics of penicillin fed-batch fermentation.CAPFM uses the three-dimensional cellular automata as a growth space,and a Moore-type neighborhood as the cellular neighborhood.The transition rules of CAPFM are designed based on mechanical and structural kinetic models of penicillin batch-fed fermentation processes.Every cell of CAPFM represents a single or specific number of penicillin producing microorganisms,and has various state.The simulation experimental results show that CAPFM replicates the evolutionary behavior of penicillin batch-fed fermentation processes described by the structured penicillin production kinetic model accordingly.展开更多
[Objectives]To optimize the solid-state fermentation process of Flos Sophorae Immaturus by Penicillium with Sophora japonica cv.jinhuai as raw material.[Methods]The fermentation conditions were optimized by single fac...[Objectives]To optimize the solid-state fermentation process of Flos Sophorae Immaturus by Penicillium with Sophora japonica cv.jinhuai as raw material.[Methods]The fermentation conditions were optimized by single factor experiment and response surface methodology with quercetin content as the dependent variable.[Results]According to the established model,the optimal fermentation process of Flos Sophorae Immaturus was obtained as follows:temperature 29.97℃,time 6.88 d,rotation speed 180.86 rpm,inoculation amount 3.93 mL,and the expected content of quercetin was 34.8053 mg/g.Based on this,the fermentation parameters were adjusted,and the actual content was 33.67 mg/g,which was close to the predicted value.[Conclusions]The optimization of fermentation process of Flos Sophorae Immaturus by response surface methodology provides a reference for the development and utilization of this medicinal material.展开更多
Traditional Chinese red sufu is a popular condiment,and typical flavor is an important indicator of sensory qualities in commercial products.In this study,the volatile aroma analysis of Wangzhihe red sufu(WRS)from dif...Traditional Chinese red sufu is a popular condiment,and typical flavor is an important indicator of sensory qualities in commercial products.In this study,the volatile aroma analysis of Wangzhihe red sufu(WRS)from different fermentation stages and four typical red sufu products from different locations was carried out by gas chromatography-mass spectrometry(GC–MS),gas chromatography-mass spectrometry/olfactory(GC–MS/O),electronic nose(E-nose)and sensory evaluation.Results showed that 106 volatile compounds were identified in Wangzhihe red sufu during fermentation process,in which phenolics and alcohols were dominant at molded and salted phetze stages,while esters and alcohols became predominate at post-fermentation stage.The volatile aroma substances varied at each fermentation stage.Furthermore,86 volatiles,including 16 aroma-active compounds,were detected in four typical red sufu products.The multivariate analysis results showed the difference in samples from different fermentation stages and typical red sufu products according to GC–MS and E-nose analysis.Combined with flavor omics,discriminant model was established for effective discrimination of samples from different fermentation stages and locations,as well as references to sufu maturity extent.The study presented a new strategy for quality evaluation of red sufu,which could be the supplement to quality evaluation standards.展开更多
Modern fermentation processes include a variety of fermentation methods,such as fed batch fermentation and continuous fermentation.This paper will focus on the principles and case studies of these two methods.Fed batc...Modern fermentation processes include a variety of fermentation methods,such as fed batch fermentation and continuous fermentation.This paper will focus on the principles and case studies of these two methods.Fed batch fermentation originates from fractionation fermentation with closed culture and adjustment of the pH value of the carbon source,to which the process of feeding the carbon source to the cell culture in a controlled manner has been added.This type of fermentation is more commonly used compared to the other.Continuous fermentation is also a closed fermentation system,which can operate without restrictions by continuous or intermittent addition of fresh nutrient media to the fermenter;however,it is susceptible to contamination by stray bacteria and metabolic inconvenience.展开更多
This paper reported the contents variation analysis ofγ-amino butyric acid(GABA)in Semen sojae praeparatum(SSP)which is a famous traditional Chinese medicine.High performance liquid chromatography(HPLC)was used and G...This paper reported the contents variation analysis ofγ-amino butyric acid(GABA)in Semen sojae praeparatum(SSP)which is a famous traditional Chinese medicine.High performance liquid chromatography(HPLC)was used and GABA was derivatized by online pre-column derivatization with o-phthalaldehyde(OPA).To validate this method,the precision,stability,repeatability and recovery were discussed.In the concentration range from 0.0125 to 0.400 mg/m L,the calibration curve for GABA was linear and the regression equation was obtained with correlation coefficient(R2)of 0.9999.Relatively high levels of GABA exist in SSP and the content changes of GABA at different time points during the fermenting process were detected.At the"yellow cladding"stage,GABA level was very low or even undetectable;the"secondary fermentation"stage witnessed a rapid increase of GABA content to 1.39-5.52 mg/g,which remained stable after 18 days of"secondary fermentation".This study demonstrated that GABA was generated at the"secondary fermentation"stage,revealing the significance and rationality of the"secondary fermentation"stage in the fermenting process of SSP.On the other hand,it suggested the downside of taking soy isoflavones as the only measurement in existing quality assessment and optimization approach for the fermenting process of SSP.展开更多
The fermentation of natural(NC)and pulped coffee(PC)was performed with a conventional method(platform)and under self-induced anaerobic fermentation(SIAF).Of the 12 samples analyzed during the fermentation process,the ...The fermentation of natural(NC)and pulped coffee(PC)was performed with a conventional method(platform)and under self-induced anaerobic fermentation(SIAF).Of the 12 samples analyzed during the fermentation process,the highest temperature was obtained by the SIAF method(30.5℃ for NC and 29.67℃ for PC)with 87 h of fermentation.Nonvolatile compounds(36 samples)were evaluated by high-performance liquid chromatography.Fermentation in the SIAF method contributed to the maximum amount of citric acid(2.534 mg/g)in pulped coffee and acetic acid(6.04 mg/g)and lactic acid(2.533 mg/g)in NC.Furan was the primary chemical class detected,followed by ketones and pyrazines.All coffees(12 samples)were evaluated five times and classified as specialty coffees(>80 points)following Specialty Coffee Association(SCA)protocols.The pulped coffee processed by the SIAF method showed a 2.83-point increase in the sensory score compared to the conventional method.Therefore,the SIAF method is accessible to producers,contributes to coffees with differentiated sensory profiles,and increases beverage quality.展开更多
Microorganisms are important sources of various natural products that have been commercialized for human medicine and animal healthcare.Bacitracin is an important antibacterial natural product predominantly pro-duced ...Microorganisms are important sources of various natural products that have been commercialized for human medicine and animal healthcare.Bacitracin is an important antibacterial natural product predominantly pro-duced by Bacillus licheniformis and Bacillus subtilis,and it is characterized by a broad antimicrobial spectrum,strong activity and low resistance,thus bacitracin is extensively applied in animal feed and veterinary medicine industries.In recent years,various strategies have been proposed to improve bacitracin production.Herein,we systematically describe the regulation of bacitracin biosynthesis in genus Bacillus and its associated mechanism,to provide a theoretical basis for bacitracin overproduction.The metabolic engineering strategies applied for bacitracin production are explored,including improving substrate utilization,using an enlarged precursor amino acid pool,increasing ATP supply and NADPH generation,and engineering transcription regulators.We also present several approaches of fermentation process optimization to facilitate the industrial large-scale production of bacitracin.Finally,the challenges and prospects associated with microbial bacitracin synthesis are discussed to facilitate the establishment of high-yield and low-cost biological factories.展开更多
基金Supported by Scientific Research Fund of Sichuan University of Science&Engineering(2011RC12,2014KY02)Scientific Research Foundation of the Education Department of Sichuan Province(15ZA0222)+1 种基金Research Project of Liquor Making Biological Technology and Application of Key Laboratory of Sichuan Province(NJ2013-06)Sichuan Provincial Undergraduate Training Programs for Innovation and Entrepreneurship(201410622021)
文摘Hyaluronic acid (HA) is a high molecular weight glycosaminoglycan consisting of alternating D-glucuronic acid and N-acetylglueasamine and plays ex- tremely important roles in many biological processes. In this study, we optimized fermentation process for the production of HA by Streptococcus zooepidemicus ATCC35246, including fermentation broth composition and various fermentation parameters. The experimental results showed that the optimal fermentation broth composition was: glucose 45 g/L, yeast extract 10 g/L, tryptone 12 g/L, KH2PO4 2 g/L, K2HPO4 . 3H20 2 g/L, MgSO4 · 7H2O 2 g/L, and (NH4 )2SO4 0.4 g/L. The optimal parameters involved in fermentation was: liquid volume 20%, pH 6. 0, rotation speed 180 r/min, fermentation temperature 35 ℃, fermentation duration 18 h, CTAB concentration 25 mg/L. Under the optimized conditions, the yield of HA was 0. 305 g/L, which was dramatically improved by 43.87% compared to that of 0. 212 g/L before optimization.
基金National Natural Science Foundation of China(No.20676013)
文摘The soft-sensor modeling for fermentation process based on standard support vector regression(SVR) needs to solve the quadratic programming problem(QPP) which will often lead to large computational burdens, slow convergence rate, low solving efficiency, and etc. In order to overcome these problems, a method of soft-sensor modeling for fermentation process based on geometric SVR is presented. In the method, the problem of solving the SVR soft-sensor model is converted into the problem of finding the nearest points between two convex hulls (CHs) or reduced convex hulls (RCHs) in geometry. Then a geometric algorithm is adopted to generate soft-sensor models of fermentation process efficiently. Furthermore, a swarm energy conservation particle swarm optimization (SEC-PSO) algorithm is proposed to seek the optimal parameters of the augmented training sample sets, the RCH size, and the kernel function which are involved in geometric SVR modeling. The method is applied to the soft-sensor modeling for a penicillin fermentation process. The experimental results show that, compared with the method based on the standard SVR, the proposed method of soft-sensor modeling based on geometric SVR for fermentation process can generate accurate soft-sensor models and has much less amount of computation, faster convergence rate, and higher efficiency.
基金Supported by the National Natural Science Foundation of China (20476007)
文摘Biomass is a key parameter in fermentation process, directly influencing the performance of the fermentation system as well as the quality and yield of the targeted product. Hybrid soft-sensor modeling is a good method for on-line estimation of biomass. Structure of hybrid soft-sensor model is a key to improve the estimating accuracy. In this paper, a forward heuristic breadth-first reasoning approach based on rule match is proposed for constructing structure of hybrid model. First, strategy of forward heuristic reasoning about facts is introduced, which can reason complex hybrid model structure in the event of few known facts. Second, rule match degree is defined to obtain higher esti- mating accuracy. The experiment results of Nosiheptide fermentation process show that the hybrid modeling process can estimate biomass with higher accuracy by adding transcendental knowledge and partial mechanism to the process.
文摘Due to its nutritional values, cassava has become an unavailable food and is one of the essential foods in the Republic of Congo. Fermentation of tubers is still traditional. Fiftyrod-shaped spore-forming bacteria were screened and carried out in batch mode for the fermentation abilities of cassava tubers in order to develop biotechnological starter. The Penetrometry Index (PI) has been used to screen bacteria and 16SrRNA as well as <i>fibE</i>one step multiplex PCR which were used to molecularly identify isolates. Emulsification Index, Proteolytic as well as amylolytic, and cellulolytic activities of some strains were quantitatively evaluated for prooving orgaleptic characterics. As results <i>Bacillus subtilis</i> (MT994787), <i>Bacillus subtillis</i> (MT994789), <i>Bacillus tequilensis</i> (MT994788), <i>Bacillus safensis</i>, and <i>Bacillus subtilis</i> have been identified. Single isolates were able to ferment tubers in 48 h and 72 hours meanwhile <i>Bacillus</i> consortia were able to shift fermentation of tubers from 48 hours to 24 hours. The consortium could be used as the major bacterial starters. Strains were associated with the ability to secrete biomolecules including biosurfactants, protease, amylase and cellulase.
基金Supported by the Postdoctoral Innovation Fund of Shandong Province(201303032)the Independent Innovation Projects of Shandong Province(2012CX20505)the National 863 High Technology Project of the Ministry of Science and Technology of China(2012AA021201)
文摘Biosensors, which are the products of the biotechnology industry, are among the key projects of the 7th, 8th, and 9th Fiveyear Plans of China Science & Technology Developing Programs, respectively, and they play an important role in developing and reforming traditional biotechnology. SBA series biosensor analyzer, as the only one commercial biosensor in China, has attracted lots of attention in the process of information gathering and measurement for biological industry with the development of technology and society. In this paper, we presented an overview of the most important contributions dealing with the monitoring of the biochemical analytes in fermentation processes using SBA series biosensor analyzers in China. Future trends of the biosensor analyzer in China were also mentioned in the last section.
基金The research is funded by Hainan University Research Funds Projects(No.kyqd1315)to serve local economic and social developmentAs a Hainan University project(2013),it is one of the Graduate Student Innovation Research Topics of Colleges and Universities in Hainan Province.
文摘Papaya,a tropical fruit was used as the raw material to produce sauerkraut in the study.Three lactic acid bacteria strains isolated from papaya were added to the sauerkraut to facilitate the fermentation of papaya sauerkraut.In the fermentation process,the dynamic changes of total acid in sauerkrauts at different levels of sugar concentration,salt concentration,inoculation and temperature were studied.The response surface method was used to study the effects of changes in multiple factors at the same time.On the basis of“one-variable-at-a-time”approach,the response surface method optimized papaya sauerkraut fermentation process.According to the change of total acid in single factor,29 experiments were designed by 4×3 factorial central composite design.The optimum fermentation conditions were obtained as follows:sugar at 3.8%,salt at 2.8%,inoculation at 5%,and temperature at 31℃.
基金supported by the National Natural Science Foundation of China (No.60274060,60375017)the Key Project of Chinese Ministry of Education (No.203002)Scientific Research Common Program of Beijing Municipal Commission of Education (NO.KM200510005026).
文摘A cellular automata model to simulate penicillin fed-batch fermentation process(CAPFM)was established in this study,based on a morphologically structured dynamic penicillin production model,that is in turn based on the growth mechanism of penicillin producing microorganisms and the characteristics of penicillin fed-batch fermentation.CAPFM uses the three-dimensional cellular automata as a growth space,and a Moore-type neighborhood as the cellular neighborhood.The transition rules of CAPFM are designed based on mechanical and structural kinetic models of penicillin batch-fed fermentation processes.Every cell of CAPFM represents a single or specific number of penicillin producing microorganisms,and has various state.The simulation experimental results show that CAPFM replicates the evolutionary behavior of penicillin batch-fed fermentation processes described by the structured penicillin production kinetic model accordingly.
基金Supported by Guilin Scientific Research and Technology Development Program(20210202-1,2020011203-1,2020011203-2)Open Project of Guangxi Key Laboratory of Cancer Immunology and Microenvironment Regulation(2022KF005)+1 种基金Guangxi Science and Technology Major Project(Guike AA22096020)Fund for Central Guiding Local Science and Technology Development(ZY20230102).
文摘[Objectives]To optimize the solid-state fermentation process of Flos Sophorae Immaturus by Penicillium with Sophora japonica cv.jinhuai as raw material.[Methods]The fermentation conditions were optimized by single factor experiment and response surface methodology with quercetin content as the dependent variable.[Results]According to the established model,the optimal fermentation process of Flos Sophorae Immaturus was obtained as follows:temperature 29.97℃,time 6.88 d,rotation speed 180.86 rpm,inoculation amount 3.93 mL,and the expected content of quercetin was 34.8053 mg/g.Based on this,the fermentation parameters were adjusted,and the actual content was 33.67 mg/g,which was close to the predicted value.[Conclusions]The optimization of fermentation process of Flos Sophorae Immaturus by response surface methodology provides a reference for the development and utilization of this medicinal material.
基金the National Key R&D program of China(2016YFD0400500)Beijing Postdoctoral Research Foundation(2018-ZZ-120)Chinese Academy of Engineering Project(2018-XY-28).
文摘Traditional Chinese red sufu is a popular condiment,and typical flavor is an important indicator of sensory qualities in commercial products.In this study,the volatile aroma analysis of Wangzhihe red sufu(WRS)from different fermentation stages and four typical red sufu products from different locations was carried out by gas chromatography-mass spectrometry(GC–MS),gas chromatography-mass spectrometry/olfactory(GC–MS/O),electronic nose(E-nose)and sensory evaluation.Results showed that 106 volatile compounds were identified in Wangzhihe red sufu during fermentation process,in which phenolics and alcohols were dominant at molded and salted phetze stages,while esters and alcohols became predominate at post-fermentation stage.The volatile aroma substances varied at each fermentation stage.Furthermore,86 volatiles,including 16 aroma-active compounds,were detected in four typical red sufu products.The multivariate analysis results showed the difference in samples from different fermentation stages and typical red sufu products according to GC–MS and E-nose analysis.Combined with flavor omics,discriminant model was established for effective discrimination of samples from different fermentation stages and locations,as well as references to sufu maturity extent.The study presented a new strategy for quality evaluation of red sufu,which could be the supplement to quality evaluation standards.
文摘Modern fermentation processes include a variety of fermentation methods,such as fed batch fermentation and continuous fermentation.This paper will focus on the principles and case studies of these two methods.Fed batch fermentation originates from fractionation fermentation with closed culture and adjustment of the pH value of the carbon source,to which the process of feeding the carbon source to the cell culture in a controlled manner has been added.This type of fermentation is more commonly used compared to the other.Continuous fermentation is also a closed fermentation system,which can operate without restrictions by continuous or intermittent addition of fresh nutrient media to the fermenter;however,it is susceptible to contamination by stray bacteria and metabolic inconvenience.
基金the National Natural Science Foundation of China(81660664,82060709,82060699)the Natural Science Foundation of Jiangxi Province(20192ACBL21032,20192BBGL70051)China Scholarship Council(201908360259)。
文摘This paper reported the contents variation analysis ofγ-amino butyric acid(GABA)in Semen sojae praeparatum(SSP)which is a famous traditional Chinese medicine.High performance liquid chromatography(HPLC)was used and GABA was derivatized by online pre-column derivatization with o-phthalaldehyde(OPA).To validate this method,the precision,stability,repeatability and recovery were discussed.In the concentration range from 0.0125 to 0.400 mg/m L,the calibration curve for GABA was linear and the regression equation was obtained with correlation coefficient(R2)of 0.9999.Relatively high levels of GABA exist in SSP and the content changes of GABA at different time points during the fermenting process were detected.At the"yellow cladding"stage,GABA level was very low or even undetectable;the"secondary fermentation"stage witnessed a rapid increase of GABA content to 1.39-5.52 mg/g,which remained stable after 18 days of"secondary fermentation".This study demonstrated that GABA was generated at the"secondary fermentation"stage,revealing the significance and rationality of the"secondary fermentation"stage in the fermenting process of SSP.On the other hand,it suggested the downside of taking soy isoflavones as the only measurement in existing quality assessment and optimization approach for the fermenting process of SSP.
基金supported by the Brazilian agencies Conselho Nacional de Desenvolvimento Científico e Tecnol´ogico(CNPq),Fundaç˜ao de Amparo`a Pesquisa do Estado de Minas Gerais(FAPEMIG)Coordenaç˜ao de Aperfeiçoamento de Pessoal de Nível Superior(CAPES)for financial support。
文摘The fermentation of natural(NC)and pulped coffee(PC)was performed with a conventional method(platform)and under self-induced anaerobic fermentation(SIAF).Of the 12 samples analyzed during the fermentation process,the highest temperature was obtained by the SIAF method(30.5℃ for NC and 29.67℃ for PC)with 87 h of fermentation.Nonvolatile compounds(36 samples)were evaluated by high-performance liquid chromatography.Fermentation in the SIAF method contributed to the maximum amount of citric acid(2.534 mg/g)in pulped coffee and acetic acid(6.04 mg/g)and lactic acid(2.533 mg/g)in NC.Furan was the primary chemical class detected,followed by ketones and pyrazines.All coffees(12 samples)were evaluated five times and classified as specialty coffees(>80 points)following Specialty Coffee Association(SCA)protocols.The pulped coffee processed by the SIAF method showed a 2.83-point increase in the sensory score compared to the conventional method.Therefore,the SIAF method is accessible to producers,contributes to coffees with differentiated sensory profiles,and increases beverage quality.
基金supported by National Key Research and Development Program of China(2022YFA0911800)Knowledge Innovation Program of Wuhan-Shuguang Project(2022020801020334)Science and Technology Project of Hubei Tobacco Company(027Y2021-023,027Y2020-013).
文摘Microorganisms are important sources of various natural products that have been commercialized for human medicine and animal healthcare.Bacitracin is an important antibacterial natural product predominantly pro-duced by Bacillus licheniformis and Bacillus subtilis,and it is characterized by a broad antimicrobial spectrum,strong activity and low resistance,thus bacitracin is extensively applied in animal feed and veterinary medicine industries.In recent years,various strategies have been proposed to improve bacitracin production.Herein,we systematically describe the regulation of bacitracin biosynthesis in genus Bacillus and its associated mechanism,to provide a theoretical basis for bacitracin overproduction.The metabolic engineering strategies applied for bacitracin production are explored,including improving substrate utilization,using an enlarged precursor amino acid pool,increasing ATP supply and NADPH generation,and engineering transcription regulators.We also present several approaches of fermentation process optimization to facilitate the industrial large-scale production of bacitracin.Finally,the challenges and prospects associated with microbial bacitracin synthesis are discussed to facilitate the establishment of high-yield and low-cost biological factories.